1. Field of the Invention
The present invention relates to a cordless telephone system capable of registering a terminal device capable of wireless communication with a telephone equipment as a child device, and relates to a telephone equipment and a terminal device included in the system.
2. Description of the Related Art
Known cordless telephone systems typically include a telephone equipment acting as a parent device and a cordless handset acting as a child device. In the cordless telephone system, when the child device is registered to the parent device for extension, the following operations are generally performed. First, a key operation that triggers child-device registration (e.g., simultaneous pushdown of a power key and a hold key) is performed for the parent device. Next, after an extension number to be allocated to a child device being registered has been inputted to the parent device, a password is inputted to the parent device. Then, a key operation that triggers child-device registration is performed for the child device. After the same extension number as that inputted to the parent device has been inputted to the child device, the same password as that inputted to the parent device is inputted to the child device. With such operations, data is transmitted and received by radio between the parent device and the child device, so that data that is required for child-device registration is exchanged. In this way, the child-device registration to the parent device is completed. Such complicated child-device registration, however, imposes a heavy load on the user. The load on the user is increased as the number of the child devices to be registered increases.
Cellular phones equipped with a wireless communication interface based on the Bluetooth specification which is one of the short-range wireless communications standards are recently in practical use. If a Bluetooth communication network (namely, piconet) is configured between a cellular phone equipped with such a Bluetooth communication interface and another telephone equipment equipped with the Bluetooth communication interface, the cellular phone can be used as a child device of the telephone equipment utilizing cordless Telephony Profile, i.e., Bluetooth profile prepared for cordless telephones. Here, a profile means a group of communication protocol for a group of products. Cellular phones, however, are rarely shared by a plurality of users as different from child devices in the conventional cordless telephone system, but are often used for private use. Accordingly, if cellular phones are intended to be used as the child devices of a telephone equipment, the number of cellular phones to be registered to one parent device must be large. Therefore, the child-device registration procedure for the cellular phone to the parent device in the same way as in the conventional cordless telephone system will impose an excess operating load on the user.